Top 25 Richest Americans Among them, I only know William Gates III (or Bill Gates [Tecnorati Tag] ), Warren Buffett, Sergey Brin, Larry Page, Michael Dell and Michael Bloomberg. See the full list of the Forbes' Richest 400 Americans. Just a kind remind, Microsoft's Gates is no longer the world's richest man and Sergey Brin married to Anne Wojcicki this May.